Spondyloarthritides.

The spondyloarthritides are a diverse group of distinct yet interrelated disease processes with overlapping clinical features. They are ankylosing spondylitis, reactive arthritis, inflammatory bowel disease-associated arthritis, and psoriatic arthritis. Genetically, these disease processes have been linked by the presence of HLA-B27. They manifest with axial and peripheral symptoms, such as inflammatory back pain, enthesitis, oligoarthritis, and dactylitis. The onset of symptoms can begin before the age of 45; however, because of the wide range of signs and symptoms, diagnosis can be delayed, leading to unchecked inflammation, structural damage, and later, restriction in physical mobility.